Not long ago, amputation of a limb for a small animal patient was quite normal when a salvage procedure was needed from trauma
Figure 10.7 Rear, right leg orthosis.
Custom Prosthetics 157
or disease. It is now being understood that the consequences of that missing limb or limb segment are not good. Organizations advocating pain management such as the American College of Veterinary Anesthesia and Analgesia, the International Veterinary Academy of Pain Management, the American College of Veterinary Sports Medicine and Rehabilitation and the American Association of Rehabilitation Veterinarians are under
standing the importance of biomechanics in normal quadruped locomotion. If a total or partial limb is missing then there can arise limited mobility and endurance, increased metabolic demand, weight gain, support limb breakdown, chronic neck and back pain, and premature euthanasia (Mich, 2014). The re‐establishment of quadruped function and structure has been made possible now in vet
erinary medicine. The end goal is to provide a limb that allows as close to normal ambula
tion as possible.
Types of Prosthesis
There are two types of prosthetic limbs available: the socket design and the ITAP (intraosseous transcutaneous amputation prosthesis). Socket‐based prostheses pro
vide a socket for the residual limb to reside in. Usually an extension (in the form of a
foot or paw) is provided for the limb to make contact with the ground (Figures 10.8–10.10). The socket prosthesis requires owner care and must be put on or removed from the patient.
Figure 10.8 Front, left leg prosthetic, lateral view. Source: Courtesy of Dr. Douglas Stramel.
Figure 10.9 Front left, leg prosthetic anterior view.
Source: Courtesy of Dr. Douglas Stramel.
Contraindications for socket prostheses may be linked to the owner, the patient, or the medical condition (Marcellin‐Little et al., 2015). Owner‐related contraindica
tions include a potential lack of interest, motivation, supervision, or financial ability to get involved. Patient‐related contraindi
cations include being difficult to handle because of an aggressive personality (Box 10.1).
ITAP provides an implanted endo
prosthesis (into the bone) to which an exoprosthesis (external prosthesis) is attached (Mich, 2014). The clear advantage of an ITAP is direct skeletal integration of the exoprosthesis (Fitzpatrick et al., 2011), and it has been shown that biological inte
gration of osseous and dermal tissues with ITAP is reliable and robust. The tremen
dous variability in veterinary patients requires adaptability in socket design, components, and prosthetic limb mechan
ics to accommodate differences in the degree of injury, body type and condition, species, breed, size, lifestyle, sport or activity, and terrain (Kaufmann and Mich, 2014) (Box 10.2).
Examples of Successful ITAP Procedures
Some procedures in which ITAP has been used successfully include:
● total hip replacement (Liska et al., 2009;
Vezzoni et al., 2015),
● total knee replacement (Mann et al., 2012),
● canine elbow arthroplasty (Burton et al., 2013), and
● titanium partial limb prosthesis in a white crane (Rush et al., 2012).
Figure 10.10 Walking with a front left leg prosthetic, anterior view. Source: Courtesy of Dr. Douglas Stramel.
Box 10.1 Contraindications for prosthetic devices in cats and dogs Owner
● Lack of interest
● Motivation
● Supervision
● Financial ability to get involved
Patient
● Difficult to handle because of an aggressive personality
Medical condition
● Highly mobile skin in relation to underlying tissues
● Neurologic deficits
● Compromised joint mobility
● Local neoplasia
● Infection
● Stump pain
Source: Marcellin‐Little et al. (2015). Reproduced with permission of Elsevier.
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Follow‐Up Care for the Prosthetic Patient
It is critical for the veterinary prosthesis patient to undergo physical rehabilitation.
The best way to ensure the highest level of success with a prosthetic device is to follow a rehabilitation plan established by a certified canine rehabilitation professional (CCRT or CCRP). Sensory feedback extends from the top down rather than from the ground up.
Through rehabilitation, the prosthesis patient relearns proprioception, balance, gaiting at different speeds, and ambulation over varied terrain (Mich, 2014). Training companion animals to use socket prostheses is similar to managing limb disuse. It relies on habituating patients to tolerate the exo
prosthesis at rest and loading it (using it) when standing, when walking slowly (indoors), when walking more rapidly (out
doors), when trotting, when galloping, and then during other activities of daily living (e.g., climbing and walking down steps, climbing and walking down stairs, jumping up, jumping down, playing) (Marcellin‐Little et al., 2015). Land‐based therapeutic exercise is essential. Balance, proprioception, muscle timing (neuromuscular retraining), and coordination lay the foundation for proper device use (Mich, 2014). These must be mastered on land so that the patient can
learn response to normal ground reaction forces and shifts in their total body force vectors (Mich, 2014).
Veterinary orthoses and prostheses are considered durable medical devices. As such, they should never be prescribed or dispensed without client training and a comprehensive follow‐up plan. Veterinary orthotic/pros
thetic patients should be assessed at least annually (Figures 10.11–10.13). Device adjust
ment and refurbishment are expected in order to continue meeting therapeutic goals (Borghese et al., 2013).
It is beyond the scope of this chapter to discuss the complete process of the veteri
nary evaluation, defining therapeutic goals, measuring for the mold cast to be sent to the prosthetic fabricator, communication with the fabricator, delivery of the device, and ensuring proper fit. Manufacturing requires skilled modification of the model by hand or using computer‐assisted design to build reliefs, which accommodate limb topography and create appropriate corrective forces when the completed device is applied to the limb. The modified model is the structure on which a thermoplastic shell is vacuum formed. The shell is then hand cut, trimmed, and ground to the final shape. Materials used to pad and line the shell vary. Hinges, straps, pads, and motion‐limiting components complete Box 10.2 Orthopedic conditions that will adapt to veterinary prosthetic devices
Thoracic limb prosthetics
● Subtotal mid‐shaft radius or ulna amputa-tion (40% antebrachium retenamputa-tion required)
● Subtotal radiocarpal disarticulation
● Subtotal intercarpal disarticulation
● Subtotal carpometacarpal disarticulation
● Amelia – a birth defect of lacking one or more limbs
● Congenital limb derangements
● Traumatic limb amputation
Pelvic limb prosthetics
● Subtotal mid‐shaft tibia or fibula amputa-tion (40% crus retenamputa-tion required)
● Subtotal tarsocrural disarticulation
● Subtotal level intertarsal disarticulation
● Subtotal level tarsometatarsal disarticulation
● Amelia – a birth defect of lacking one or more limbs
● Congenital limb derangements
● Traumatic limb amputation
Source: Adapted from Kaufmann and Mich (2014).
Figure 10.11 Double limb prosthetics for hindlimbs, lateral view. Source:
Courtesy of Dr. Douglas Stramel.
Figure 10.12 Double limb prosthetics for hindlimbs, rear view. Source:
Courtesy of Dr. Douglas Stramel.
Figure 10.13 Double rear limb prosthetics during exercise.
Source: Courtesy of Dr. Douglas Stramel.
References 161
fabrication. The typical custom veterinary orthotic/prosthetic device cost varies with com
ponents and materials, but averages US$600–
$US1000. This does not include the necessary appointments to ensure proper fit and function along with client education (Mich, 2014).
Where Do I Go?
Professional companies that fabricate these devices are listed at www.animaloandp.com/
facilities.asp. Companies that are highly recommended include:
● OrthoPets™ (www.orthopets.com/)
● Animal Ortho Care, LLC (www.ani malorthocare.com)
● Advanced Care Veterinary Services (www.
stoppetpain.com)
● Dogs in Motion Canine Rehabilitation;
OrthoPets Australia (www.dogsinmotion.
com.au)
● Equisport Medicine; OrthoPets Washington (www.equisportmedicine.com)
● K‐9 Orthotics & Prosthetics (www.k‐
9orthotics.com)
● A Loyal Companion; OrthoPets Arizona (www.aloyalcompanion.com)
● OrthoPets Europe; Elmtree House (www.
orthopets.co.uk)
● Pawsitive Steps Rehabilitation Clinic;
OrthoPets Michigan (www.pawsitivestep srehab.com)
● Paws on the Go; OrthoPets Southern California (www.pawsonthego.net)
● Twin Cities Animal Rehabilitation Clinic;
OrthoPets Twin Cities Minnesota (www.
tcrehab.com)
● Veterinary Orthopedic and Sports Medicine Group (VOSM) (www.vetsportsmedicine.
com)
● A Well Adjusted Pet; OrthoPets San Francisco (www.awelladjustedpet.com)
● Wheat Ridge Veterinary Specialists (www.
wheatridgeanimal.com)